Open vSwitch daemons accept certain commands at runtime to control
their behavior and query their settings. Every daemon accepts a
common set of commands documented under COMMON COMMANDS below. Some
daemons support additional commands documented in their own manpages.
ovs-vswitchd in particular accepts a number of additional commands
documented in ovs-vswitchd(8).
The ovs-appctl program provides a simple way to invoke these
commands. The command to be sent is specified on ovs-appctl's
command line as non-option arguments. ovs-appctl sends the command
and prints the daemon's response on standard output.
In normal use only a single option is accepted:
-t target--target=target
Tells ovs-appctl which daemon to contact.
If target begins with / it must name a Unix domain socket on
which an Open vSwitch daemon is listening for control channel
connections. By default, each daemon listens on a Unix domain
socket named /usr/local/var/run/openvswitch/program.pid.ctl,
where program is the program's name and pid is its process ID.
For example, if ovs-vswitchd has PID 123, it would listen on
/usr/local/var/run/openvswitch/ovs-vswitchd.123.ctl.
Otherwise, ovs-appctl looks for a pidfile, that is, a file
whose contents are the process ID of a running process as a
decimal number, named
/usr/local/var/run/openvswitch/target.pid. (The --pidfile
option makes an Open vSwitch daemon create a pidfile.)
ovs-appctl reads the pidfile, then looks for a Unix socket
named /usr/local/var/run/openvswitch/target.pid.ctl, where pid
is replaced by the process ID read from the pidfile, and uses
that file as if it had been specified directly as the target.
On Windows, target can be an absolute path to a file that
contains a localhost TCP port on which an Open vSwitch daemon
is listening for control channel connections. By default, each
daemon writes the TCP port on which it is listening for
control connection into the file program.ctl located inside
the configured OVS_RUNDIR directory. If target is not an
absolute path, ovs-appctl looks for a file named target.ctl in
the configured OVS_RUNDIR directory.
The default target is ovs-vswitchd.
-T secs--timeout=secs
By default, or with a secs of 0, ovs-appctl waits forever to
connect to the daemon and receive a response. This option
limits runtime to approximately secs seconds. If the timeout
expires, ovs-appctl exits with a SIGALRM signal.

Every Open vSwitch daemon supports a common set of commands, which
are documented in this section.
GENERAL COMMANDS
These commands display daemon-specific commands and the running
version. Note that these commands are different from the --help and
--version options that return information about the ovs-appctl
utility itself.
list-commands
Lists the commands supported by the target.
version
Displays the version and compilation date of the target.
LOGGING COMMANDS
Open vSwitch has several log levels. The highest-severity log level
is:
off No message is ever logged at this level, so setting a logging
destination's log level to off disables logging to that
destination.
The following log levels, in order of descending severity, are
available:
emer A major failure forced a process to abort.
err A high-level operation or a subsystem failed. Attention is
warranted.
warn A low-level operation failed, but higher-level subsystems may
be able to recover.
info Information that may be useful in retrospect when
investigating a problem.
dbg Information useful only to someone with intricate knowledge of
the system, or that would commonly cause too-voluminous log
output. Log messages at this level are not logged by default.
Every Open vSwitch daemon supports the following commands for
examining and adjusting log levels.
vlog/list
Lists the known logging modules and their current levels.
vlog/list-pattern
Lists logging pattern used for each destination.
vlog/set [spec]
Sets logging levels. Without any spec, sets the log level for
every module and destination to dbg. Otherwise, spec is a
list of words separated by spaces or commas or colons, up to
one from each category below:
· A valid module name, as displayed by the vlog/list
command on ovs-appctl(8), limits the log level change
to the specified module.
· syslog, console, or file, to limit the log level change
to only to the system log, to the console, or to a
file, respectively.
On Windows platform, syslog is accepted as a word and
is only useful if the target was started with the
--syslog-target option (the word has no effect
otherwise).
· off, emer, err, warn, info, or dbg, to control the log
level. Messages of the given severity or higher will
be logged, and messages of lower severity will be
filtered out. off filters out all messages.
Case is not significant within spec.
Regardless of the log levels set for file, logging to a file
will not take place unless the target application was invoked
with the --log-file option.
For compatibility with older versions of OVS, any is accepted
as a word but has no effect.
vlog/set PATTERN:destination:pattern
Sets the log pattern for destination to pattern. Each time a
message is logged to destination, pattern determines the
message's formatting. Most characters in pattern are copied
literally to the log, but special escapes beginning with % are
expanded as follows:
%A The name of the application logging the message, e.g.
ovs-vswitchd.
%B The RFC5424 syslog PRI of the message.
%c The name of the module (as shown by ovs-appctl --list)
logging the message.
%d The current date and time in ISO 8601 format
(YYYY-MM-DD HH:MM:SS).
%d{format}
The current date and time in the specified format,
which takes the same format as the template argument to
strftime(3). As an extension, any # characters in
format will be replaced by fractional seconds, e.g. use
%H:%M:%S.### for the time to the nearest millisecond.
Sub-second times are only approximate and currently
decimal places after the third will always be reported
as zero.
%D The current UTC date and time in ISO 8601 format
(YYYY-MM-DD HH:MM:SS).
%D{format}
The current UTC date and time in the specified format,
which takes the same format as the template argument to
strftime(3). Supports the same extension for sub-
second resolution as %d{...}.
%E The hostname of the node running the application.
%m The message being logged.
%N A serial number for this message within this run of the
program, as a decimal number. The first message a
program logs has serial number 1, the second one has
serial number 2, and so on.
%n A new-line.
%p The level at which the message is logged, e.g. DBG.
%P The program's process ID (pid), as a decimal number.
%r The number of milliseconds elapsed from the start of
the application to the time the message was logged.
%t The subprogram name, that is, an identifying name for
the process or thread that emitted the log message,
such as monitor for the process used for --monitor or
main for the primary process or thread in a program.
%T The subprogram name enclosed in parentheses, e.g.
(monitor), or the empty string for the primary process
or thread in a program.
%% A literal %.
A few options may appear between the % and the format
specifier character, in this order:
- Left justify the escape's expansion within its field
width. Right justification is the default.
0 Pad the field to the field width with 0s. Padding with
spaces is the default.
width A number specifies the minimum field width. If the
escape expands to fewer characters than width then it
is padded to fill the field width. (A field wider than
width is not truncated to fit.)
The default pattern for console and file output is
%D{%Y-%m-%dT %H:%M:%SZ}|%05N|%c|%p|%m; for syslog output,
%05N|%c|%p|%m.
Daemons written in Python (e.g. ovs-xapi-sync) do not allow
control over the log pattern.
vlog/set FACILITY:facility
Sets the RFC5424 facility of the log message. facility can be
one of kern, user, mail, daemon, auth, syslog, lpr, news,
uucp, clock, ftp, ntp, audit, alert, clock2, local0, local1,
local2, local3, local4, local5, local6 or local7.
vlog/close
Causes the daemon to close its log file, if it is open. (Use
vlog/reopen to reopen it later.)
vlog/reopen
Causes the daemon to close its log file, if it is open, and
then reopen it. (This is useful after rotating log files, to
cause a new log file to be used.)
This has no effect if the target application was not invoked
with the --log-file option.

This page is part of the Open vSwitch (a distributed virtual
multilayer switch) project. Information about the project can be
found at ⟨http://openvswitch.org/⟩. If you have a bug report for
this manual page, send it to bugs@openvswitch.org. This page was
obtained from the project's upstream Git repository
⟨https://github.com/openvswitch/ovs.git⟩ on 2019-05-09. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2019-05-08.) If you discover any rendering problems in
this HTML version of the page, or you believe there is a better or
more up-to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not part
of the original manual page), send a mail to man-pages@man7.org
Open vSwitch 2.11.90 ovs-appctl(8)